1. Field of the Invention
The invention relates to a power conversion technique, and more particularly, to an inverting apparatus and a photovoltaic power system using the same.
2. Description of Related Art
In a typical photovoltaic power system, a front-end photovoltaic module (such as solar panel) is generally disposed outdoors to receive sunlight. However, the photovoltaic module disposed outdoors is inevitably affected by climate and environment, and therefore has the risk of damage.
For instance, a photovoltaic ground terminal of the photovoltaic module may be in a floating state due to climate impact, such that the photovoltaic ground terminal of the photovoltaic module and a device ground terminal of a back-end inverting apparatus have different potentials. Such a phenomenon is referred to as a ground fault of the photovoltaic module. In a ground fault condition, a leakage current is generated between the photovoltaic ground terminal and the device ground terminal due to potential difference. Excessive leakage current may cause electric shock to the user or the occurrence of fire.
In current techniques, a low-frequency signal injection method or a variable-frequency signal injection method is generally adopted to detect the issue of ground fault of the photovoltaic module. However, current methods all need to apply complex circuit architectures, and cannot accurately detect the occurrence of a ground fault.